1M0M

BACTERIORHODOPSIN M1 INTERMEDIATE AT 1.43 A RESOLUTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.43 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.163 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystallographic structure of the retinal and the protein after deprotonation of the Schiff base: the switch in the bacteriorhodopsin photocycle.

Lanyi, J.Schobert, B.

(2002) J.Mol.Biol. 321: 727-737


  • PubMed Abstract: 
  • We illuminated bacteriorhodopsin crystals at 210K to produce, in a photostationary state with 60% occupancy, the earliest M intermediate (M1) of the photocycle. The crystal structure of this state was then determined from X-ray diffraction to 1.43 A ...

    We illuminated bacteriorhodopsin crystals at 210K to produce, in a photostationary state with 60% occupancy, the earliest M intermediate (M1) of the photocycle. The crystal structure of this state was then determined from X-ray diffraction to 1.43 A resolution. When the refined model is placed after the recently determined structure for the K intermediate but before the reported structures for two later M states, a sequence of structural changes becomes evident in which movements of protein atoms and bound water are coordinated with relaxation of the initially strained photoisomerized 13-cis,15-anti retinal. In the K state only retinal atoms are displaced, but in M1 water 402 moves also, nearly 1A away from the unprotonated retinal Schiff base nitrogen. This breaks the hydrogen bond that bridges them, and initiates rearrangements of the hydrogen-bonded network of the extracellular region that develop more fully in the intermediates that follow. In the M1 to M2 transition, relaxation of the C14-C15 and C15=NZ torsion angles to near 180 degrees reorients the retinylidene nitrogen atom from the extracellular to the cytoplasmic direction, water 402 becomes undetectable, and the side-chain of Arg82 is displaced strongly toward Glu194 and Glu204. Finally, in the M2 to M2' transition, correlated with release of a proton to the extracellular surface, the retinal assumes a virtually fully relaxed bent shape, and the 13-methyl group thrusts against the indole ring of Trp182 which tilts in the cytoplasmic direction. Comparison of the structures of M1 and M2 reveals the principal switch in the photocycle: the change of the angle of the C15=NZ-CE plane breaks the connection of the unprotonated Schiff base to the extracellular side and establishes its connection to the cytoplasmic side.


    Organizational Affiliation

    Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BACTERIORHODOPSIN
A
262Halobacterium salinarum (strain ATCC 700922 / JCM 11081 / NRC-1)Mutation(s): 0 
Gene Names: bop
Find proteins for P02945 (Halobacterium salinarum (strain ATCC 700922 / JCM 11081 / NRC-1))
Go to UniProtKB:  P02945
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
LI1
Query on LI1

Download SDF File 
Download CCD File 
A
1-[2,6,10.14-TETRAMETHYL-HEXADECAN-16-YL]-2-[2,10,14-TRIMETHYLHEXADECAN-16-YL]GLYCEROL
LIPID FRAGMENT
C42 H86 O3
YERVUJAKCNBGCR-BIHSMRAKSA-N
 Ligand Interaction
RET
Query on RET

Download SDF File 
Download CCD File 
A
RETINAL
C20 H28 O
NCYCYZXNIZJOKI-OVSJKPMPSA-N
 Ligand Interaction
SQU
Query on SQU

Download SDF File 
Download CCD File 
A
2,10,23-TRIMETHYL-TETRACOSANE
LIPID FRAGMENT
C27 H56
ZADHKSJXSZBQFB-HHHXNRCGSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.43 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.163 
  • Space Group: P 63
Unit Cell:
Length (Å)Angle (°)
a = 61.069α = 90.00
b = 61.069β = 90.00
c = 110.099γ = 120.00
Software Package:
Software NamePurpose
SHELXphasing
SCALEPACKdata scaling
SHELXmodel building
SHELXL-97refinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2002-06-13 
  • Released Date: 2002-09-11 
  • Deposition Author(s): Lanyi, J.K.

Revision History 

  • Version 1.0: 2002-09-11
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2015-09-09
    Type: Version format compliance